const buf= Buffer.alloc(26);
for(let i= 0;i< 26;i++ ){
    buf[i]=i+ 97;
}
console.log(buf.toString('ascii'));
// >abcdefghijklmnopqrstuvwxyz
console.log(buf.toString('utf-8',0,5));
// >abcde
console.log(buf.toString(undefined,5,26));
// >fghijklmnopqrstuvwxyz